The concept of an adjustable bed has been known for some time. Early adjustable beds utilized several motors to adjust a bed frame upon which an articulated mattress rested. A typical articulated mattress might be divided into three, four or more sections each mounted upon an adjustable frame section and each driven by an electric motor. Examples of adjustable beds utilizing at least two motors may be found in the following patents: U.S. Pat. No. 2,500,742 by A. J. Taylor; U.S. Pat. No. 2,582,565 by E. V. Schnippel, et al.; U.S. Pat. No. 3,262,133 by S. W. Beitzel; and U.S. Pat. No. 3,644,946 by L. W. Swatt.
Early adjustable beds were manufactured and sold to hospitals and convalescent homes where individuals could be expected to be confined to a bed for an extended period of time. However, with an increasingly affluent society, the market for adjustable beds has been expanding to home usage. During this same time period, the economy has experienced a general inflation. Thus, it is desired to provide an adjustable bed with as few components as possible for economy while retaining as many comfort features as possible.
One component which could be eliminated is the use of a second motor. An example of a single motor adjustable bed wherein the motor is a hydraulic pump which uses two hydraulic cylinders may be found in U.S. Pat. No. 2,520,849 by G. D. McVicker. Another adjustable bed arrangement in which a single motor drives two adjustable sections through a transmission is found in U.S. Pat. No. 3,191,196 by L. E. Holm or U.S. Pat. No. 3,278,952 also by L. E. Holm. A hospital bed utilizing a single motor and three clutches to obtain adjustment of an articulated mattress is shown in U.S. Pat. No. 3,465,373 by H. A. Wilson.
While the foregoing examples represent various approaches for powering an adjustable bed, each of the adjustable beds shown in the examples cited and known in the prior art require complicated drive mechanisms when but a single motor is utilized.